The decision tree: Live smarter, live longer

This article was taken from the March issue of Wired UK
magazine. Be the first to read Wired's articles in print before
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Life is complicated -- especially when it comes to our health.
Once we reach a certain age, we start to realise that health is a
variable, not a constant. Our knees ache, our place slow, and we're
diagnosed with diabetes or even cancer.

And because the stakes are so high and the options so dizzying,
we may stop engaging with our health altogether. We let doctors and
insurance companies decide on our care, and we focus our energies
on what we can control -- our bank accounts, our relationships, but
not, alas, our health. That's too bad, because health is really
just a system of inputs and outputs.

The inputs include the choices we make: what we eat, whether we
exercise, how much we sleep, whether we heed our doctors' orders.
These decisions combine with other inputs, things that we may not
even consider information and that we probably know much more about
than our doctors, such as our family history, where we live, our
jobs, our stress levels, and so on. All of these inputs create one
primary output unique to us alone: our health, for good or ill.

This means we have more control over our health than we might
have thought. By monitoring and tweaking our inputs, we can
influence and even determine our well-being. Taken all at once, our
health may seem inscrutable; laid out in a sequence, it becomes a
series of decisions, each with risks, benefits and trade-offs. In
other words, we can organise our health options into a decision
tree, a method for factoring in our inputs, mapping out our options
and guiding us along the best possible path.

A decision tree is a simple idea -- many of us learned to draw
them (in the form of flowcharts) in primary school. And decision
trees are already all around us. They're common in engineering and
industry, where they're known as algorithms. The pharmaceutical
industry uses them to plan safe clinical trials. Financial service
quants use them to root out credit-card fraud. They're even used by
city planners to design street patterns and map bus routes. In
these cases, decision trees can be complicated tools, laden with
mathematics and computer science.

But they needn't be only for the experts. In an age of too much
information and too little illumination, a decision tree can be a
tool that nudges any of us to think carefully through our options
and to act consciously and with consideration. A decision tree can
be as straightforward as a list of the pros and cons of a
particular option that we complete before we act. It can
be a simple and useful way to turn the health data we already have
into a system for better choices and better outcomes.

And auspiciously, we're at a moment when more data than ever
lies within ready reach. Whether it's personal-genomics services
such as 23 and Me or self-tracking iPhone apps, each of us can draw
on a wealth of personalised data sources that turn generic medical
advice into customised health equations. And this is always-on
data. Instead of checking in on our health episodically - when we
visit the doctor or get lab test results -- we can now tap into a
constant stream of information and opportunity. We can minimise our
uncertainty and maximise our control. We can build ever more
sophisticated, and useful, decision trees.

In the following pages, you'll meet three individuals, each
facing a different medical quandary. As their experiences show, the
right decision tree can bear the fruit of a better life.